The High Energy X-ray Timing Experiment (HEXTE)

The HEXTE consisted of two clusters each containing four `phoswich
scintillation detectors. Each cluster could ``rock'' (beamswitch)
along mutually orthogonal directions to provide background measurements
1.5 or 3.0 degrees away from the source every 16 to 128 s. Automatic
gain control was provided by using a 241Am radioactive source
mounted in each detector's field of view. The HEXTE's basic properties
are:

Energy range: 15 - 250 keV

Energy resolution: 15% at 60 keV

Time sampling: 8 microsecond

Field of view: 1 degree FWHM

Detectors: 2 clusters of 4 NaI/CsI scintillation counters

Collecting area: 2 times 800 cm^2

Sensitivity: 1 Crab = 360 count/s per HEXTE cluster

Background: 50 count/s per HEXTE cluster

Events detected by HEXTE were processed on board by its own data
system before insertion into the telemetry stream at an average
data rate of 5 kbit/s. Data products included event mode, binned
spectra and light curves, and a burst-triggered event buffer.